1. Field of the Invention
This invention relates to a copy magnification change apparatus in a magnetic copying machine, and more particularly to a copy magnification change apparatus in a magnetic copying machine which can be suitably applied to a magnetic duplicator by which numerous copies can be automatically and speedily obtained from one original copy.
2. Description of the Prior Art
The Japanese Patent Publication No. 19793/1963 discloses a magnetic copying machine in which an image of a document is recorded as a magnetic latent image on a recording drum by a magnetic head, the magnetic latent image is sequentially developed, transferred and fixed onto a recording paper to obtain a copy. In the magnetic copying machine, the image of the document can be recorded as the magnetic latent image in enlargement on the recording drum. The ratio of a diameter of a document winding drum to a diameter of the recording drum is predetermined for enlargement. Further, the ratio of a speed of read-out means to a speed of the magnetic head in horizontal direction is predetermined for enlargement by a gear speed change mechanism. Generally, when a magnetic copying machine has copy enlarging function and/or copy reducing function, it is desired that it has further actual-size copying (magnification factor: 1) function. For example, when a copy of A4-size is obtained from a document of B4-size by a magnetic copying machine, it is desired that a copy of A4-size can be obtained from a document of A4-size by the same magnetic copying machine and that the copy magnification factor can be easily changed over by simple operation, for example, by operation of a switch arranged on a panel. In the above-described prior art, for example, the ratio of the diameter of the one drum to that of the other drum should be changed for different magnification factors. That is not simple operation.
Further in an electro-static copying machine using Xerography method, a lens system should be moved for copy enlargement and copy reduction by a complicated mechanism. Since copy magnification is changed in mechanical manner, changing operation of copy magnification requires much time.